I mentioned last month that we were pretty close on the new amplifiers and now it is time to introduce some details for everyone here. There will be three series of amplifiers available in 2 through 8 channels each. We have been calling these amp series the 1000, the 1250, and the 1500 around the lab as that represents the maximum output at the speaker output of each with all channels driven as established by their respective power supplies after all efficiency losses. No doubt you can expect a naming contest on these from Amie shortly.

First and foremost I would like to thank Andrew, our resident master of all things audio. These new amps are his brainchild and represent the culmination of over 2 years of work by Andrew on the designs. I cannot say enough about how impressed I and the whole Axiom team are with the results of his work on these projects. They are spectacular. But it goes far beyond the new amplifiers; Andrew’s on-going work on all the products at Axiom has been amazing and we’re so fortunate to have him with us. Improvements driven by Andrew are having a positive influence on our entire line-up of products. The innovation he is driving has added so much excitement and energy to both our products and the people working on them, and I’d like to thank him very much for his contributions. We are all looking forward to an exciting future with lots of both great new products and great improvements to our existing ones, with Andrew driving forward what we can accomplish.

These amps will be ready for shipping on July 20 though we will have a few available earlier for anyone who has purchased LFR1100s. They all come in the same chassis. It is a really heavy duty chassis made from 2mm steel with a 9mm aluminum face panel. The height is 3U for all of them. All these new amplifiers are Class-D amplification with massive analog power supplies and they are all north of 90% efficient at full power. This efficiency is an important benefit to our amps. A typical Class-AB design is around 50% efficient which means that ½ of the output from the transformer is wasted off in heat which is quite limiting to your overall output with all channels driven (given a single power cord on a regular 15amp circuit). The maximum you can extract from a typical wall plug is 1800 watts. Given a reasonably efficient and absolutely massive power supply you can end up with somewhere around 1650 watts available to the amplifiers. So at north of 90% efficiency you can easily achieve 1500 watts of total output (hence our 1500 series lab name). But at 50% efficiency you are limited to around 825 watts. That is a massive difference in a multi-channel amplifier. Below is a little chart that shows how the output power works for each of our amplifier series:

When considering what power is right for you it is important to keep in mind that in a typical home theatre system the power demands from the surround channels are much less than the front three so you will tend to have more power available where you need in the real world. A 7-channel amp utilized in a home theatre system will tend to act more like the 5-channel for power per channel as shown in the above chart.

As for the inputs available, the 1000 Series is RCA only. Both the 1250 Series and the 1500 Series have both RCA inputs and fully balanced XLR inputs. All the amplifiers can be powered with 100 volts, 120 volts, or 240 volts depending on what is available in your country. This is easily selectable inside the chassis but we will pre-set it at the factory for the country it is being shipped to.

As for the pricing I have created another chart below which shows the price of each model in its respective number of channels. We will also be doing a 2-tiered pre-order deal similar to what we did with the LFR1100.

All these new amplifiers are Class-D amplification with massive analog power supplies and they are all north of 90% efficient at full power. This efficiency is an important benefit to our amps. A typical Class-AB design is around 50% efficient which means that ½ of the output from the transformer is wasted off in heat which is quite limiting to your overall output with all channels driven (given a single power cord on a regular 15amp circuit). The maximum you can extract from a typical wall plug is 1800 watts. Given a reasonably efficient and absolutely massive power supply you can end up with somewhere around 1650 watts available to the amplifiers. So at north of 90% efficiency you can easily achieve 1500 watts of total output (hence our 1500 series lab name). But at 50% efficiency you are limited to around 825 watts. That is a massive difference in a multi-channel amplifier. Below is a little chart that shows how the output power works for each of our amplifier series:

Ian, or Andrew, what is the rating of the power supply?

I also find it interesting that the rating for a typical wall outlet was included; this is something that i think often gets over looked.. With the 1500, would the recommendation be to have a dedicated breaker on the outlet that the 1500 would be plugged into? It might be prudent in older houses, where there are more outlets on fewer breakers..

In the interest of cost-savings, would it be feasible to buy a 3-channel model for FL,C,FR and let my receiver drive the surrounds? Or would this result in a channel volume level mismatch at high volumes where the receiver's power ratings can't keep up with the Axiom?

Henry, the way I read Ian's chart is that Axiom will configure each amp with anywhere from 2 to 8 channels based on consumer preference. I don't think there would be any problem doing what you envision; your receiver would be able to adjust the levels accordingly.

From a basic technology standpoint, the building blocks of the amplifiers (Class D amplifiers strapped to a high current linear power supply) remain true to the earlier design. However, all of the individual elements are ground up designs, and this includes the way the amplifiers are assembled. Technology races on and there are new and far more sophisticated devices available today that were unheard of 6 years ago, and these are incorporated into all of the new amplifiers.

This is a really good idea. Not only do you end up with some real power where you need it across all the front channels, you will now be designating the entire power supply of your receiver to the surround channels. This will give them added power also since almost always the limiting factor in a receiver is not the power per channel but the overall power available as determined by the power supply.

Andrew, I currently have a 3808. How much better will these amps sound ?

Oh, and will it sound better than my multicoloured tube amp? I can't tell a difference between my tube amp and my 3808 (unless I'm looking at the pretty colours), so I'm looking to add a little "colour" to my speakers using a modest looking amp.

Speaking of tube amps, my friend who's totally def really likes mine. He claims he can hear a difference. I'm confused, but I'm not questioning him. Not because I don't want to, but because I can't do sign because I can't move my fingers.

Our communication is very arduous and frustrating. He writes down what he thinks I'm going to say or ask, and upon eventually getting it right, he responds. Needless to say, he hasn't been over in a while. I tried calling him the other day to touch base, but after the phone rang a couple times, I couldn't hear anything. I'm going to stop at his place tomorrow to see how he's doing. His apartment complex has stairs, but thankfully I can reach the button to buzz his apartment.

OK while we all wait for the official 'name the new amps' contest, how about an entirely unofficial contest to come up with the best 'unofficial' name for your favorite Axiom product. Who knows, maybe some will be used in the fine print of the upcoming product brochures?

Power, I missed when you got a tube amp, please enlighten me with the details.

I was just being goofy, dude.

As I've mentioned numerous times, I thought my RPA-1 sounded better than my 3801. But, being the realist that I am, my shear excitement of setting up a new separate amp could've caused this perceived improvement in sound; I'll never know.

Speaking of tube amps, my friend who's totally def really likes mine. He claims he can hear a difference. I'm confused, but I'm not questioning him. Not because I don't want to, but because I can't do sign because I can't move my fingers.

"Why, I can hardly hear it! You'd have to be deaf to hear that."--Murray, Flight of the Concords--

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With great power comes Awesome irresponsibility.

Does this design reroute unused power to the other channels needing the power, like Tom's design, that was a nice feature?

I know that Ian said that it does act in this way, but I am not understanding how. From the table Ian gave on the first post, on the 1500 series amp, it says that with one channel driven there is 325 Watts into 8 Ohms. That figure remains pretty consistent as more channels are driven into the same load. The previous Axiom amp was able to dump all of the power supply, the whole 1500 Watts when one channel is driven. This seems like a different design that Tom's in this regard. Though with real world material, 325 Watts should be more than enough, for even the most demanding material.

The table shows continuous power output figures. This is power that you have available for any length of time that it might be required. What we have not stated is peak or instantaneous power ratings and this is where you are able to momentarily sink far more power into the load than the continuous numbers suggest. This is the power supply "steering" that you are thinking of from the A1400 and the new amplifiers all have this same capability.

I know that Ian, Amie, and Steve are all hard at work with creating the web pages for these new amplifiers. They will feature more in-depth specifications. Is there something specific that you'd like to know? The power ratings that Ian gave in his original post are at 1% THD+N.

The table shows continuous power output figures. This is power that you have available for any length of time that it might be required. What we have not stated is peak or instantaneous power ratings and this is where you are able to momentarily sink far more power into the load than the continuous numbers suggest. This is the power supply "steering" that you are thinking of from the A1400 and the new amplifiers all have this same capability.

Yes, but if there are two, three, or four channels driven then there is also 325 Watts continuous power available to each channel. When 5 channels are driven the number drops to 300 Watts available continuously to each channel, since there is only 1500 Watts that can be had out of the wall. My question is: If 1500 Watts can be split up between the channels so that there is approximately 300 Watts continuously given to each channel, then why can't there be 1500 Watts continuously given if there is only one channel driven? Or 750 Watts if only two channels are driven? Was this limited to 325 Watts continuous since there are some speakers that cannot handle more than than on a over a period of time, or am I missing something? I still don't really understand.

Yes, but if there are two, three, or four channels driven then there is also 325 Watts continuous power available to each channel. When 5 channels are driven the number drops to 300 Watts available continuously to each channel, since there is only 1500 Watts that can be had out of the wall. My question is: If 1500 Watts can be split up between the channels so that there is approximately 300 Watts continuously given to each channel, then why can't there be 1500 Watts continuously given if there is only one channel driven? Or 750 Watts if only two channels are driven? Was this limited to 325 Watts continuous since there are some speakers that cannot handle more than than on a over a period of time, or am I missing something? I still don't really understand.

Ok, I can see where you are having trouble. It's a little difficult because there are two factors at play here. On the one hand we have this large power supply that can supply lots of "power" to how ever many channels need it. On the other we have to look at the amplifiers themselves. By definition, an amplifier cannot swing or deliver more than the available DC power supply voltage to a load (speaker). Once we take losses, including the amplifier's efficiency, into account, the available voltage swing is reduced even further. It's this voltage swing that determines the maximum, continuous output power that the amplifier can deliver into a given load, assuming that we have unlimited current available. So, even though we might be able to deliver 1500 watts from the power supply, the amplifier is limited by the rail voltage.

Time for some quick math:

Let's assume P is power, V is voltage, I is current, and R is resistance. I'm going to leave the complex reactive speaker impedance out of the discussion and assume the load is purely resistive!

P = V x IFrom Ohm's Law we know that I = V/RSubstituting this equation into the first equation we get:P = (V x V)/R

In the A1500 we are running +/-85Vdc rails, which means the peak to peak voltage is 170Vdc. However, we can only swing voltage in one direction or the other at a given time. This means we need to use our peak voltage, which is 85Vdc. Power is usually, somewhat erroneously, specified in watts RMS, so we need to convert peak voltage into RMS voltage. To do this we multiply the peak voltage by the square root of 2 (0.707).

Going back to our original power equation, our maximum output power into 8ohms is:

P = (60.095 x 60.095)/8 = 451.23 watts

But wait a second, this assumes that the entire amplifier is 100% efficient, which it's not. We need to apply the approximate efficiency to the RMS voltage, and this is 90% in the A1500. This gives an actual RMS voltage swing of

V = 60.095 x 0.9 = 54.0855

Redoing our power calculation now gives:

P = (54.0855 x 54.0855)/8 = 365.66 watts

So this is the maximum single channel output power, no matter how much current is available from the power supply. Why does Ian's table state 325 watts for one channel? Because we're still in the preproduction stages of these designs and we wanted to be conservative until the final numbers are in. I hope that was not too hard to follow and helps to clarify the continuous power ratings.

I am under the impression, that amps which have power ratings that do not double as load impedance halves varies their rail voltage...If the rail voltage is held constant, then as the impedance halves the power output should double, infinitely in a theoretical situation.

Going off of Ians' chart the rail voltage that Andrew provided, the rail voltage remains constant until there are 3 channels driven at 100%, at which time the rail voltage reduces when a 4ohm load is present. At 3 channels driven @100%, the rail voltage should reduce to approximately 46Vrms or 77% of 60.095 Vrms. the 77% reduction in voltage is representative of the difference between 650W and 500W.

I am under the impression, that amps which have power ratings that do not double as load impedance halves varies their rail voltage...If the rail voltage is held constant, then as the impedance halves the power output should double, infinitely in a theoretical situation.

Going off of Ians' chart the rail voltage that Andrew provided, the rail voltage remains constant until there are 3 channels driven at 100%, at which time the rail voltage reduces when a 4ohm load is present. At 3 channels driven @100%, the rail voltage should reduce to approximately 46Vrms or 77% of 60.095 Vrms. the 77% reduction in voltage is representative of the difference between 650W and 500W.

Do i have a correct conceptual understanding of how this works?

The rail voltage remains constant until we reach the maximum continuous current capability of the power supply, at which time the rail voltage will reduce or "sag". This is why the power output drops at a certain point when more channels are added. At that point the maximum rail voltage is no longer the limiting factor in output power, it's now the supply current and the subsequent drop in rail voltage. If we had an unlimited supply current available, the power output would keep doubling at each halving of the load impedance until we reach the current limits of the amplifier output stage, which has current limiting protection. On the A1500 this will not take place until you're down into sub-2ohm territory.

Andrew, forgive a naive question, but is there such a thing as "speed" of the amp?

Way back when, I went from a NAD 2200PE to a receiver and felt something was missing. I can only describe it as missing some "liveness" that I was perceiving as a lack of transients...drums, cymbals, a "roughly" played and close-miked acoustic guitar.

I'm not sure if there was a "speed" issue, or it was a matter of having huge reserves for those very short attacks(?).

I used to read of damping factors, etc... which I don't see as much info on anymore.

Andrew, forgive a naive question, but is there such a thing as "speed" of the amp?

Way back when, I went from a NAD 2200PE to a receiver and felt something was missing. I can only describe it as missing some "liveness" that I was perceiving as a lack of transients...drums, cymbals, a "roughly" played and close-miked acoustic guitar.

I'm not sure if there was a "speed" issue, or it was a matter of having huge reserves for those very short attacks(?).

I used to read of damping factors, etc... which I don't see as much info on anymore.

I guess there are several terms, such as slew rate and damping and rise time which are sometimes, and sometimes not, published.

I just don't know how important they are. Seems like Damping Factor used to be touted everywhere, and now, not so much.

I don't know if their importance has been found to be less than initially thought, or if it's just a matter of marketing, or what.

OK, I hear the groans from bringing up an amp discussion. But I've got a chance to ask someone who designs them.

Here's the real meat of it: JohnK always states that all amps are the same, assuming a flat frequency response. But are there other factors that can make an amp better than another other than FR?

I know the discussion has been beaten to death over the years, but I'm still trying to determine if that perceived difference 15 years ago was false (it certainly COULD have been, it was nowhere near an instantaneous switch!!) or if there are factors that come into play beyond a "flat frequency response".

My Denon AVR-3808CI has a built-in 130 watt internal amplifier for each speaker. I know not all AVR's are like the older Japan-built Denon's. Would adding one of these amp's make any difference in my case? Based on room size, the 1000 series would be what I need, but at 8 Ohms, the 125 watts this amp delivers is already below what the 3808 claims to supply.

I was wondering how many Watts the 1000 was in 8 ohms. It's 125. I think for my setup a 1000 series with 6 amps would be perfect. Maybe someday I can make that happen. My next upgrade would be 2, preferably 3 QS8's to complete a 6.1 system.

Not sure what color to go with though. All the other speakers are black, except the subwoofer, which is Cinnamon Beech. Perhaps Cinnamon Beech would be good for the QS8's also. No reason they have to be black.

I doubt that the difference you heard from your NAD amp to other amps would be related to the speed, or slew rate. The slew rate difference in amplifiers is measured in micro seconds and is not likely to contain any audible difference. The power reserves you mentioned are very likely the reason though. NAD amps tended to be low continuous power with good head room and a nifty soft clipping circuit. This soft clipping circuit would keep the usual harshness associated with clipping to a minimum but you would still lose some of that “attack” we all like that comes from being able to actually cleanly reproduce the dynamic peak requested in the original source.

The difference you are wondering about really comes down to the power supply. Coincidently I wrote a little piece about this in our newsletter today. I suspected it would be a question many people would have. Receiver power is almost always rated at the RMS power per channel with one channel driven or with the remaining six channels running at 1/8 power. This means that 130 watts per channel is either 17 watts or 32 watts per channel with all channels driven. Beyond the weak all channels driven power receiver amplifiers are generally also hard limited at the max power rating, 130 watts in your case. This lack of dynamic head room means any required short burst of power above 130 watts will not be reproduced. In some ways quite similar to the type of problem Mark was commenting on.

Ian, thanks for the info. For some time I've been wondering if an amp would be beneficial for my system or just overkill. I'm going to be closely watching the developments here over the next few months. I still need to figure out how the 1000 would be incorporated into my set-up and what sort of cables would be best to connect it to my AVR. You may have just introduced me to my Christmas present to myself this year.

Mark, as Ian and Chris point out, what you were referring to is termed "slew rate". This is the rate at which the amplifier changes voltage level over time. The usual parameter is given in volts per micro second. When a frequency during music appears which is higher(faster)than the previous frequency or is louder, the amplifier has to supply more voltage because of the higher level and do it more quickly because of the higher frequency. This is needed to produce that note at the required level and with low distortion. Note that this has nothing to do with sharper transient response or a perceived "tighter, quicker" sound; it's just doing the frequency accurately with low distortion.

The required slew rate at any instant in time is given by 2 x pi x freq. x voltage(peak). For example, to reproduce 20,000Hz at 100 watts(i.e. 40V peak, 28V RMS for 100 watts into 8 ohms, since power equals voltage(RMS)squared/impedance)the slew rate would be about 6.28 x 20,000 x 40 = 5,240,000(in micro-volts)or a slew rate of 5.24 volts per second.

This number contrasts with numbers on the order of 50, 100 or even more which some amplifiers proclaim, and is unrealistically high as is, because no music recordings require full power at 20,000Hz. Many years ago Baxandalltested LPs for maximum slew rate required and found that 0.5 volt per second was all that was needed. British amplifier designer Michael Renardson updated this work for CDs, as shown here and found a maximum requirement for 100 watts into 8 ohms of 2.5 volts per second(would be 5 volts per second for 400 watts). All receivers/amplifiers of a high fidelity standard handle a band width to 20KHz or more at full rated power, and slew rate isn't a problem with any of these units. Making it 10 or more times higher than required is of no audible benefit and may increase costs.

On the amp "sound" point, you've left out some requirements given beyond flat frequency response, e.g., inaudibly low noise and distortion, and should note holding other factors equal, particularly matching sound levels to within 0.1dB when running blind tests. The same point always has to be repeated: all an amplifier does is add more voltage, and all more voltage does is make the sound louder. If this would ever change it wouldn't be in audio forum discussions, but might be published in my AES journal and possibly lead to a Nobel Prize in Physics.

Technology races on and there are new and far more sophisticated devices available today that were unheard of 6 years ago, and these are incorporated into all of the new amplifiers.

I'm curious to read more on what this statement entails, and what it means for real-world performance.

Here's a shortlist of the "big ones":

Lower distortion, particularly at low power outputs where the amplifier spends most of its time operating.

Higher efficiency.

Cooler idling temperature.

Better control of output stage switching = excellent long term reliability.

Extremely robust and instantaneous protection circuitry for major fault conditions.

I have a question about #2. Lower distortion at lower output levels. This and possibly in combination with other parameters in the amps design. My question is.

Have you found through either the development phase, comparisons to other amplification (like receivers which we all use) or just living with the product in your home testing different source material and more importantly different speakers, if this amp can provide sound quality benefits even at low to moderate listening levels?

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I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

My Denon AVR-3808CI has a built-in 130 watt internal amplifier for each speaker. I know not all AVR's are like the older Japan-built Denon's. Would adding one of these amp's make any difference in my case? Based on room size, the 1000 series would be what I need, but at 8 Ohms, the 125 watts this amp delivers is already below what the 3808 claims to supply.

I have a 4311CI rated at 140W per channel with 9 channels. Can it drive all 9 channels simultaneously at 140W, no, not even close. The detailed specs list 9 channels at 140W but right below that list is something they refer to as Dynamic Power and it lists 150W x 2 Channels. In reality 150W with two channels driven is what the amp can really do and in my experience just by looking at the size and weight of the transformer, I would believe that.

Actually with movies having a scene that would demand full volume out of all channels is quite rare I think. So even though the Denon specs are misleading, they could probably defend their claim.

Just about a month ago, I took an ancient Bryston 3B I had in storage and hooked it up to the Denon preamp out of the Front L/R to drive my M80s. This made a significant improvement for some movies. Two movies I can point out are Tron and Super 8. The train crash scene of Super 8 is awesome for testing; there are loud crashing sounds from all speakers. As the Denon no longer had to drive the M80s, it had significantly more power available for the center, surrounds and backs. Overall, adding the Bryston has made a noticible overall improvement.

It's funny; the new Axiom amps arrived just at the right time for me. My 25 year old Bryston (and yes I bought it almost new... sigh, I feel so old) is nice but is a power hog and although still sounds clean is based on technology close to 30 years old. So, after hearing the improvement an external amp makes when used with my fronts, I already have put in my pre order for a A1000.

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For every expert, there is an equal and opposite expert.

I hope that was not too hard to follow and helps to clarify the continuous power ratings.

This was very easy to follow, thank you for explaining this so well. I understand now.

Originally Posted By: Andrew

Once we take losses, including the amplifier's efficiency, into account, the available voltage swing is reduced even further. It's this voltage swing that determines the maximum, continuous output power that the amplifier can deliver into a given load, assuming that we have unlimited current available. So, even though we might be able to deliver 1500 watts from the power supply, the amplifier is limited by the rail voltage.

Since the +/- 85Vdc rails seem to be a limiting factor in how much continuous power can be delivered to an one channel at a time, then why don't designers simply go with rails rated with a larger figure? For example if there were a +/- 170Vdc rail, then running the calculations would give approximately 1500 Watts for one channel. Is this a big added expense to the overall design, or just not possible because of some other reason? Or maybe that people don't need 1500 Watts continuous power delivered to one channel?

I'm not trying to be difficult, but am just trying to understand the basics of amplifier designs with my very limited knowledge.

My Denon AVR-3808CI has a built-in 130 watt internal amplifier for each speaker. I know not all AVR's are like the older Japan-built Denon's. Would adding one of these amp's make any difference in my case? Based on room size, the 1000 series would be what I need, but at 8 Ohms, the 125 watts this amp delivers is already below what the 3808 claims to supply.

I have a 4311CI rated at 140W per channel with 9 channels. Can it drive all 9 channels simultaneously at 140W, no, not even close. The detailed specs list 9 channels at 140W but right below that list is something they refer to as Dynamic Power and it lists 150W x 2 Channels. In reality 150W with two channels driven is what the amp can really do and in my experience just by looking at the size and weight of the transformer, I would believe that.

Actually with movies having a scene that would demand full volume out of all channels is quite rare I think. So even though the Denon specs are misleading, they could probably defend their claim.

Just about a month ago, I took an ancient Bryston 3B I had in storage and hooked it up to the Denon preamp out of the Front L/R to drive my M80s. This made a significant improvement for some movies. Two movies I can point out are Tron and Super 8. The train crash scene of Super 8 is awesome for testing; there are loud crashing sounds from all speakers. As the Denon no longer had to drive the M80s, it had significantly more power available for the center, surrounds and backs. Overall, adding the Bryston has made a noticible overall improvement.

It's funny; the new Axiom amps arrived just at the right time for me. My 25 year old Bryston (and yes I bought it almost new... sigh, I feel so old) is nice but is a power hog and although still sounds clean is based on technology close to 30 years old. So, after hearing the improvement an external amp makes when used with my fronts, I already have put in my pre order for a A1000.

Boltron, thanks for the reply. I was hoping to get some real-world, relatable advice like this from someone with a similar receiver. I'm starting to understand the advantages an amp would afford my system. After you get your 1000, please let us know your thoughts. I'd especially be intersted in how warm the unit gets.

I can’t believe I may have just found someone looking for more power than even I would consider enough. At some point the power per channel is out of the range of being of any sort of limitation. Using a 3-channel 1500 series amp to power the three front channels (M80s and a VP180) you would have 700 watts of power available to each them with a total shared power of 1500 watts available (a separate 4-channel amp could be used for the surrounds). This may be getting close to all anyone would need but don’t quote me on that.

I notice now that in my previous reply, although I correctly defined slew rate in terms of volts per microsecond, in the examples I typed "second". The numbers are correct, but the time unit should of course be microseconds(millionths of a second).

Hi, I'm new to the Axiom forum but have been receiving the newsletter. I met all of you briefly at Le Salon Son et Image in Montreal this year.I'm glad to see the amps are available before the fall. I own an Anthem MRX 700rated at 120 watts 2 channels driven and 90 watts 5 channels driven from 20hz to 20khz at 0.1% distortion @ 8 ohms. Also have speakers with built in powered subs.

Always been interested in buying one of your power amps, now is my chance. I was looking at the 1000 series 3 channel amp or the 1250 series 3 channel amp. Is there an upgrade option if I decide to go 5 channels later? Like listening to movies at realistic levels same with music. Is an upgrade really needed. Room is average size.

Was even thinking about changing the power cord on the MRX 700???Thoughts and ideas would be appreciated. Thanks, enjoyed catching up on some forum topics.

So, back to the new amps. I'm seriously considering the new Axiom amps. And, of course, would want to take advantage of the early order savings. I would be interested in learning the difference between the new Axioms on the others around using the Ice Power modules? How doe they differ? How are they better?Time is running short on this decision :-)

Hi Amie, You have the first part right as in Wawa. JB in French a wawaron is a male bull frog. I do live in Wawa and am male so wawaron. Next time in town let me know we can go for coffee at the best restaurant in Wawa which happens to be outside of Wawa, the Kinniwabi Pines. Best coffee and meals around.

The ICE amp module is also a switching amp and will share those high efficiencies for converting wall current to power at the speaker. But when we originally looked into the possibility of using the ICE amp modules they came with their own switching power supply as part of each module. We found this limiting to one of our main design parameters of having a massive analog power supply available to all of the channels. Beyond this show stopper, there were also the limitations of the module itself. Though it would be easy to implement for sure, we really wanted more control over every aspect of the amp design, which designing from the ground up gave us.

The amps are 17.75" wide for the face panel and 17.5" wide for the chassis. I have let Brent know we changed the spec on the site as well. The last day for the first level of the pre-order pricing is tomorrow. No problem with all the questions, I am sure they are a big help to everyone reading this.

Thanks Ian,Now I just have to decide between the 1250 or the 1500.I have a pair of Paradigm Studio 100v4 and the big 690 center. The room is large; 15 x 25 x 9. But it is also open into a kitchen dinette area. What are your thoughts here?

I notice that the home amplifiers page mentions that they "can be configured in 1 to 7 channels," but then in another paragraph it says that they can drive up to eight channels. Not that that affects me. I was simply curious.

Wow, no activity for quite a while. So I'll start some. I'm anxiously awaiting shipping on my new 1500. Delayed a bit due to a big response to early discounts. A good thing I suppose.I'm just wondering. What type of "break in" if any is suggested with these new monsters?

Ooh, I got a shipment notification today. I really wish Axiom would specify what was being shipped in those notifications, though. It's fine for people who are only waiting on one thing, but for people who are expecting a number of items to ship, it would be nice to know which one(s) made it out.

My ADA1000 3ch (with serial number that ends in 001) just arrived this morning! I unpacked it and it looks awesome. I unfortunately can't try it out till later in the day I'll post later once I get to hook it up and do some calibration.

Doin that happy happy dance...

Edited by Boltron (08/17/1209:56 AM)

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For every expert, there is an equal and opposite expert.

As those of you who are still waiting for your orders already know, we are still running quite behind on shipping. We’re really sorry. We have what we feel confident is a firm production schedule now:

We’ll finish shipping the ADA1000s by the middle of next week; the ADA 1250s will follow immediately after that and take 1.5 weeks to complete, and then due to order volume, the ADA1500s will ship out daily during the two weeks that follow.

Orders are shipping in the order in which the amplifiers were purchased for each model.

Again, our apologies for this very long delay in getting the amps sent out. We know you’ll love the added depth and power in your home theater system, and hopefully that will help make up for the wait!

I have a 4 channel 1500. When I originally posted I was using it to drive a pair of M80 v3's. This was via pre-outs from my Denon 4802 receiver. (I was only using 2 channels because...) I have now changed my setup and am driving my new LFR 1100's (front and rear) from the ADA 1500.

I've got 5yr old Epic 80-500 system, which I love. Its driven by similiar aged Onkyo 805. Apple Lossless music on the PC, routed to the stereo via Apple TV (controled by iPad). My room is a great room, which opens into dining and kitchen and hallway. Total square feet of all open areas totals about 800-900. 15ft vaulted ceiling. I've just come into a few bucks, and might be interested in this new amp. That's a LOT of dough though, for just power. I've got two young kids, so rarely get to crank the volume. I watch a fair amount of movies, and listen to a fair amount of music (although not 'critically' as much anymore, just due to time). So, if I go with a ADA1250 or ADA1500 (3 channels), will I REALLY notice a major improvement? Or will the difference be minor, and only when I get the house to myself so I can really crank it up?

In my experience you should notice a difference even at lower volumes by adding a separate amp, but as you said the biggest difference is when you get to crank it up. I still haven't bought a separate amp despite my desire to get one, I just feel it to big a price to pay for the slight/but noticeable improvements. YMMV

I've got 5yr old Epic 80-500 system, which I love. Its driven by similiar aged Onkyo 805. Apple Lossless music on the PC, routed to the stereo via Apple TV (controled by iPad). My room is a great room, which opens into dining and kitchen and hallway. Total square feet of all open areas totals about 800-900. 15ft vaulted ceiling. I've just come into a few bucks, and might be interested in this new amp. That's a LOT of dough though, for just power. I've got two young kids, so rarely get to crank the volume. I watch a fair amount of movies, and listen to a fair amount of music (although not 'critically' as much anymore, just due to time). So, if I go with a ADA1250 or ADA1500 (3 channels), will I REALLY notice a major improvement? Or will the difference be minor, and only when I get the house to myself so I can really crank it up?

For me the difference was big enough that I picked up another amp (used) for the other channels. Not just when I crank it!

I have a 4 channel 1500. When I originally posted I was using it to drive a pair of M80 v3's. This was via pre-outs from my Denon 4802 receiver. (I was only using 2 channels because...) I have now changed my setup and am driving my new LFR 1100's (front and rear) from the ADA 1500.

Did you add a center channel to your DSP?What are you using for your center channel speaker and amplification?

I did add the centre in the DSP but there was no easy way to use it at first. So I was just using the receiver to drive the centre and surrounds. I've more recently added a used 3 channel amp which for the centre channel is connected thru the DSP. I will soon be swapping out my receiver for a used preprocessor.

I recently added a 1500 series amp with 8 channels to my system. I had been running a 1400-8 since 2008, however some of the channels failed, more than once as the amp was upgraded and Axiom stood behind the amp all the way through the process and gave me a very generous option to upgrade from the 1400 to the 1500 series. I am running a Denon 3808ci receiver with a v2 7 channel Axiom ep80-qs8-vp180-800 system. Overall I have preferred the sound from the Axiom amp infinitely more than the Denon, in my room; however, the biggest difference I noticed was when the channels supporting the M80s died. There was just no contest in the comparison between the Axiom amp and the Denon internal amplification, it was killing me just to listen to how anemic it sounded. My surrounds I believe are mounted a bit high so I'm not clear about how important having the whole 8 channels driven by the digital amp is, yet my sense is that the soundstage seems more integrated with the 1500 amp driving all channels than when I had the Denon/Axiom amp combo in force.

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"If you try to turn toward it, you go against it."

I was using an older model Denon receiver before and totally agree that the separate amp is a big improvement. I also agree that this is most noticeable on the front channels but this may in part be due to my relativity lower quality (non-Axiom) surrounds.

Brent twisted my shoulders on an ASA1500-3. Should ship this upcoming Friday (7-5). I vacilate between really excited and reserved/skeptical. I'm looking forward to the 30 day trial for sure. Will be looking for a marked improvement in soundstage/imaging/dynamic response at moderate levels. I don't expect much at low levels, and I'm sure I'll experience the difference at high volume (due to the huge room my setup is in- well over 5000 cubic feet). I'll let you all know what comes of it!-Brady

Got it yesterday. Hooked it up last night. Wife on the couch with me paying bills (she is not nearly into this stuff as I am, and has no clue what this amp cost). First up: Seal's Kissed by a Rose (acoustic version). I heard percussion instruments I had not heard before. But, maybe I was just paying more attention? I turned my head to ask my wife, when she blurted out "I can totally hear the mirimba. that was NOT there before!!" She put the bills down.Next up, Keb Mo's Closer. Again, incredible detail. Again, I turned me head to get the wife's feedback. She had tears dripping off her face. She says: "do NOT return this amp!!" This is one of her favorite songs, that she's heard numerous times.

I could tell you more, but that's that pretty much sums it up. And were listening a "moderate levels" as the kids were asleep.

The M22s would be a great match for an ADA1000 amp. The dynamic range of music and movies requires lots of power to be available when needed. All of our ADA series amps have not only high power output continuously available per channel but they can also deliver bursts of power well beyond those ratings. It really makes the whole experience so much more realistic to have this kind of power in reserve in your system.

Thanks Ian. After reading the descriptions of them, I'd probably be happier with the ADA1250, 3 channel amp for L/C/R, where each has 2 sets of 8 ohm speakers per channel, then let the receiver drive the 3 QS8's.

And that's how I've set-up my system, with the 1500 driving the fronts and center, and the 805 driving the surrounds. Really works great. No problem with sounds panning from surrounds to fronts, that I can tell. And the over-all effect is MUCH more, how to say this, engrossing? enveloping? Its less like you're listening to the movie and more like you're in the middle of the movie, if that makes sense. And I agree, voltage=voltage, shouldn't make any difference if it comes from an Onyko receiver or an Axiom amp, right? Only thing I can figure is, even at moderate volumes, the power required to fill my big great room (10,000+ cubic ft?) with sound is way more that the Onkyo can cover at all times, and thus distorts to a certain degree. While the ADA1500 has no problem, with room to spare, even at high volume (which I've experienced btw, and its just wicked cool). I really feel like, for the first time, I've stepped completely into this mystical "Audiophile" world. Cool place to be.

And that's how I've set-up my system, with the 1500 driving the fronts and center, and the 805 driving the surrounds. Really works great. No problem with sounds panning from surrounds to fronts, that I can tell. And the over-all effect is MUCH more, how to say this, engrossing? enveloping? Its less like you're listening to the movie and more like you're in the middle of the movie, if that makes sense. And I agree, voltage=voltage, shouldn't make any difference if it comes from an Onyko receiver or an Axiom amp, right? Only thing I can figure is, even at moderate volumes, the power required to fill my big great room (10,000+ cubic ft?) with sound is way more that the Onkyo can cover at all times, and thus distorts to a certain degree. While the ADA1500 has no problem, with room to spare, even at high volume (which I've experienced btw, and its just wicked cool). I really feel like, for the first time, I've stepped completely into this mystical "Audiophile" world. Cool place to be.

As you can see there was a wink at the end of my reply. I have from the start advocated getting an external amp (I run a Rotel RB1080) and buy as much power as you can comfortably afford. I'm glad your liking your new toy; enjoy. This was long before it was popular.

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Rick

"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud

Bayne, you should check out the class of operation for those amps that interest you;class D runs very cool, and class A/B runs much warmer.class F, as on my amps, runs very cool too, but maybe a little bit warmer than class D. the warmest air coming out of my amps, at the fan outlet, is about 40 Celsius.

I never thought I would write a post like this, but hey... there is a first for everything :-). Maybe because I always thought Axiom should focus on speakers?I read the review as well; I'm just not sure how they award products. There is a better, cheaper, more powerful A/B class 5 channel amp that beats the ADA in every category... except power consumption maybe.I'm not saying the amps are no good.... far from it, but "Exceptional Value" award?

I never thought I would write a post like this, but hey... there is a first for everything :-). Maybe because I always thought Axiom should focus on speakers?I read the review as well; I'm just not sure how they award products. There is a better, cheaper, more powerful A/B class 5 channel amp that beats the ADA in every category... except power consumption maybe.I'm not saying the amps are no good.... far from it, but "Exceptional Value" award?

What amp are you referring to ??. Remember that those of us who live in Canada must pay duty and shipping when buying from the states. Also factor in return shipping < < hassle if you have to return it for any reason. The Axiom is upgradeable to more channels, doesn't require a dedicated power outlet, doesn't require a forklift to install and leaves some room for other components, it runs cool and heat is the enemy of pretty much anything man made, including man LOL. As I get older price is not my only consideration, I also take into account customer service. A similar amp from Bryston is 8 grand.

No one is offended here. Honestly I thought the same as you when I recently started looking at amps. As I said I prefer to source from a Canadian company and there isn't a lot to choose from. I tend to keep my stuff a long time, so long term the price is in line. When I was 16 (35yrs ago) I paid almost a grand for my integrated amp 65w/ch so 3g for 5 channels 250w/ch doesn't seem out of line. I have never bought anything based on a review so it has no sway for me one way or the other. I prefer owners experience's more than anything,which is why I come here.

As a happy long time "Axiomite"....since 1991, I have watched this company grow and I am happy to see the success.

I do find it funny that over the years this forum has looked down upon $1k, $2k, 3k products, claiming that cost does not mean performance or value. Now our lil' Axiom is offering products in those price points and we are happy with those products and costs.

Not looking to argue this, or intending to offend anyone, just and observation. YMMV

BB I myself have not been around all that long so I may have missed some of those threads. I know 4 or 5 years ago I was looking at Emotiva and having trouble scratching together money for that. But as time goes along im finding I can treat myself a little better. TBH I don't need a 5 or 7 channel amp with 200w/ch but I want one just the same The price may seem too high to some, acceptable to others and a real bargain to people with a higher income. I choose to drive a crappy car and have other toys I value more. What I like about the ADA's is the small footprint and more than enough power for my small room. Also I like hearing other people's input about these sorts of things , not much fun if everyone was of the same opinion. I cant speak for anyone else but I definetly am not offended by what people say about axiom , whether good or bad.

I think it is important to remember, for quite some time now both with speakers and amps, Axiom has had a pretty close relationship with Bryston(another Canadian company)and I have never heard people complain about the prices of their amps. Also remember the Emotiva stuff is ALL built in China, hence, the considerably cheaper prices. For Canadians, even though one were to import Emotiva from the US, because it is built in China and it has to be displayed like that on their paperwork, there is an automatic 6.5% duty plus brokerage fee added on top of everything else.

Myself, in the recent past, has purchased amps from Outlaw and all but one of their models is assembled in the US, so I am actually supporting an American company(built by ATI in California). Even though the Outlaw amps are comparatively more expensive than the Emotiva stuff, since the country of origin is shown as the US, all duty and depending on your carrier(hopefully not UPS)most brokerage fees are waived, which, when you add everything up, closes the gap with the Emotiva prices.

My next amp(s) will be from Axiom even if I have to wait longer to save up for one (or two). As we all know, in recent years there has been a lot of consolidation in the CE industry which often, doesn't necessarily always bode well for product quality AND after market service. I would rather have a company like Axiom, be able to survive and thrive on its own even if it means opening my wallet a little more.

I would rather have a company like Axiom, be able to survive and thrive on its own even if it means opening my wallet a little more.

Well said. This is a stance I find myself starting to take more and more recently.

I have some questions for anyone willing though(and please bare with me, for I'm not to up on all this technical jargon).

The ADA1500 1 channel says it's max output is 325 watts for 8 ohm and 650 watts for 4 ohm. Exactly double. So the M80v3 being a 4 ohm speaker, does that mean the 1 channel ada1500 has an available 650 watts to give to it?

The 2 channel says the same exact specs though

The 3 channel is still 325 at 8, but 500 watts at 4 ohm.

The 5 channel is 300 watts at 8 and 300 at 4 ohm.

I don't get it. Every other amp manufacturer's specs always seem to have higher numbers for "4 ohm", regardless of number of channels. It seems as the channels increase, so does lack of power.

I don't mind paying the money at all, especially if it's for axiom. But I really am hoping to be able to have an available 500 watts for every speaker in my 5 channel setup. I still have to end up with a product I need a want.

To go that route, it looks like I'd have to buy a 2 channel ada1500 and a 3 channel ada1500. That's a lot of dough

Alternatively, the Emotiva XPR-5, shipped to my door, I was quoted $2700 total, that includes all fees, taxes and duties. It says it has an available 600 watts for every one of the 5 channels, simultaneously, at 4 ohm.

How does this work? Is axiom just being much more honest with their specs? I understand the emotiva is an a/b, while the ADA is a class D...does this have anything to do with it?

I personally think the axiom is a much better product and of course isn't made in china, so I understand the raise in cost.

I'm not really trying to concentrate on the price. My questions more relate to how and why the specs work as they do.

Those are good questions , maybe Andrew will stop by and educate us. This is a copy/paste from the amp page.

Understanding the Equation

Although output with eight-channels driven looks small, the fact of the matter is that the power demands from surround channels in a home theater system are much smaller than the power demands of the front left, right and center speakers. As a result, the real-world experience with these amps is lots of power available for the power-hungry front section. a seven-channel amplifier used in a home theater system acts more like a five-channel amp for power-per-channel, as shown in the chart above.

I take this to mean that since the surround channels don't contain a lot of information their power demands are low . This would leave the amp capable of supplying the front 3 channels with the 500 watts specified. No sure why anyone would need that much power anyway ,especially with how efficient the Axiom speakers are. Typical listening requires often less than 1 watt/ch. The Emo amp is definitely a beast and the specs are impressive though I cant seem to find any 3rd party tests to verify its output. I love the internet, shopping from my chair

The XPR 5 needs a 20A dedicated circuit, class AB is not as efficient.

I am rereading the whole thread, maybe This will help, scroll about half way down.

Well to preface...at the ear damaging levels I like my music, I definitely use more than 1 watt. I want to be able to achieve,120db...just because I can :p. After retiring my defect rotel...i just cant get it close to loud enough. Plus, I prefer extended stereo for music...i want(perhaps more than I need :p ) 500 watts available for every channel.

I'll start with a 3 channel ada and go from there tho. Who knows...maybe ill be pleased enough with that time to start saving.

I am glad you brought this up. I decided to read the thread from the beginning and pages 4 and 5 had the answers we both wanted. A typical receptacle can provide only so much current, and the ADA 1500 has to work within those constraints. Even if you buy 2 amps they will have to be on separate circuits or a dedicated circuit added by your friendly electrician. .

And yeah if ya like it loud and you like power then I say get it. I am all for over indulgence lol. I like it loud too and now im goin deaf. Everything is a compromise in life.

That makes sense. Thanks. installing a new dedicated circuit isnt a problem. Its in the plans

Im going on 15 years of standing in front of electric guitar amps and loud music...i get hearing tests yearly through work and i'm still doing great. Itll catch up with me eventually though i'm sure lol

Lucky you It's only been the past 3yrs, started in my late 40's. Mostly the tinnitus, though it comes and goes. Keep us apprised of your choice. I am hoping to get a 5 ch ada-1500 , nothing says I cant add another down the road

Power Requirements: 115 VAC or 230 VAC +/- 10% @ 50 / 60 Hz (user selectable). The XPR-5 requires a 20 Amp circuit and standard IEC 20 Amp outlet (which is different than a 15 Amp outlet).If you don’t have a proper circuit and outlet, we recommend you have one installed by a qualified electrician.We recommend that the XPR-5 be plugged into its own dedicated 20 Amp circuit. From http://shop.emotiva.com/collections/amplifiers/products/xpr5

The Axiom amps are designed for standard 15 amp circuit. That probably explains the discrepancy.

EDIT: In fact, all the XPRs require a 20 amp circuit. Better add the install cost of that puppy to your total amp price!

I dont understand why people are making a big deal of the install of a seperate 20 amp circuit and outlet? Its quite simple and won't cost me much.

I wasnt trying to steer the conversation into a "A VS B" type of thing. I was just using that particular brand as an example to demonstrate numbers. I feel the axiom amp is a much better product quality wise. I dont understand what discrepancy you are referring to?

And Im still am hoping someone can answer my earlier questions. Why, with outlaw, rotel, emotiva, etc...do the 4 ohm specs always appear to be much more than the 8 ohm specs...while on an ada, they are the exact same as soon as you hit 5 channels?

I understand now, that fitting in the constraints of a 15amp circuit, as the number of channels increase, power per channel decreases. But still curious about my other questions. Is axiom just being more honest with their specs?

There are many things to consider when looking at amp specs. The most important in my mind is the fact that a speaker is not a constant resistive load. The M80 only drops to 4ohm in certain frequency ranges Impedance graph

Amps are not asked to produce continuous high power levels, it is transient and most power is required by the woofers so if your using a sub and not powering the lower frequencies the required power is much lower. This is why sub amps are such high power .

Read the posts on page 4 and 5 of this thread by Andrew, it explains something that is really quite complicated in an easy to understand fashion that even I can wrap my mind around.

I am not sure what other questions you had other than why some amps double their power into 4 ohms. The AdA amps do up to point where the power supply can no longer maintain current to the rails. 3 channels seems to be the limit ,If they used an even larger power supply and 20A circuit they could maintain rail voltage over more channels.

Andrew WelkerThe rail voltage remains constant until we reach the maximum continuous current capability of the power supply, at which time the rail voltage will reduce or "sag". This is why the power output drops at a certain point when more channels are added. At that point the maximum rail voltage is no longer the limiting factor in output power, it's now the supply current and the subsequent drop in rail voltage. If we had an unlimited supply current available, the power output would keep doubling at each halving of the load impedance until we reach the current limits of the amplifier output stage, which has current limiting protection. On the A1500 this will not take place until you're down into sub-2ohm territory.

If you want to evaluate the validity of continuous amplifier power output claims, all that's required is some simple math.In North America, with a typical 15A AC circuit at 120V, you can draw a maximum of 1800 watts. For a 20A circuit you can draw a maximum of 2400 watts. Now that's simply what you can get out of the wall, not what you can get to your speakers, because no amplifier+power supply can be 100% efficient. Class AB amplifiers with linear power supplies typically range from 50-65% and Class D amplifiers can range from 80-95%. So, for a 5-channel Class AB amplifier with 50% efficiency to continuously supply 600 watts to all channels would require 6000 watts from your household AC, not to mention having to dissipate an enormous amount of heat...

If you want to evaluate the validity of continuous amplifier power output claims, all that's required is some simple math.In North America, with a typical 15A AC circuit at 120V, you can draw a maximum of 1800 watts. For a 20A circuit you can draw a maximum of 2400 watts. Now that's simply what you can get out of the wall, not what you can get to your speakers, because no amplifier+power supply can be 100% efficient. Class AB amplifiers with linear power supplies typically range from 50-65% and Class D amplifiers can range from 80-95%. So, for a 5-channel Class AB amplifier with 50% efficiency to continuously supply 600 watts to all channels would require 6000 watts from your household AC, not to mention having to dissipate an enormous amount of heat...

Andrew, my takeaway from this is that Emotiva's claims are baseless. Something else that came to mind for me is the fact that , typically one room is on a single breaker. So not only am I feeding my amp , I am powering a 60" plasma , my receiver , my dvr or bluray player etc which doesn't even allow my amp access to that 1800 watts. I have a killawatt meter and my tv takes 300 on its own.

Andrew, my takeaway from this is that Emotiva's claims are baseless. Something else that came to mind for me is the fact that , typically one room is on a single breaker. So not only am I feeding my amp , I am powering a 60" plasma , my receiver , my dvr or bluray player etc which doesn't even allow my amp access to that 1800 watts. I have a killawatt meter and my tv takes 300 on its own.

Richard

This is a very good point but remember, it is virtually impossible with any music or movie programme material to actually require full output for all amplifier channels at the same instant in time. Also remember that your the impedance of your loudspeaker varies with frequency. When we publish a continuous power rating it will always be with a 1kHz sine wave driving a purely resistive 8 or 4 ohm load. These kinds of bench test conditions are nice for defining an apples to apples baseline for power output, but they represent the kind of worst-case scenario that will likely never be seen in the context of an actual system.

Thanks for clarifying that Andrew, I tend to get ahead of myself when I am typing and leave things out. I realize music is transient and speakers are a constantly changing load (impedance). It is much the same with cars, dyno tests are a good measuring stick for comparison, but no one put's there car up against a building and floors it . Amplifier rating (and horsepower) are some of the most over exaggerated specs. We as humans love MORE, and it is an easy way for marketers to get our attention without being clear about what we are buying. I look forward to purchasing an ADA amp and the fact that they are efficient makes it all the more desirable.

I read through this thread and managed to get all the info I needed, but what would be great is if all this info was in one place as a sticky or maybe something in your blog.

Those linear power supplies (which prefer to draw their line current in big horrible spikes, and would love a chance to intermodulate your music with rectified line voltage), combined with the inherent nonlinearities in both class AB and D output stages, tend to complicate amplifier design a bit more than Andrew is letting on.

Using huge capacitor banks, minimizing dead time (in class D), raising bias current (in AB), shielding, etc. all reduce the distortion and noise somewhat, but what really makes the difference is the control loop.

What makes the Axiom amps better than the previous generation of class D (and what I'm surprised I haven't heard people talking about) is the way they generate their switching signals; they are essentially self-oscillating delta sigma modulators (similar to a lot of ADCs / DACs). The control loop in this type of amp acts as a low-pass filter for any signal that shows up at the input, but a high-pass filter for the noise that's generated inside the amp. This essentially separates the "good" and "bad" signals into different frequency ranges, with the "bad" being moved up where you can't hear it, and then directed right into the stop-band of the output filter. It also lends itself to tight control with high loop gain over the whole audio spectrum, and allows the control loop to accurately account for the time the output stage spends in between the rails.

I could see it being sensitive to higher frequency EMI though.. hence the linear supply?

I'm still thinking on how to drive all my speakers.... One question on the Axiom Amp is why the toroidal PS over Switch Mode PS?

This might sound like a trite answer but it's not intended that way... since AFAIK typical power amplifier power supplies are not regulated there's no inefficient linear regulator to replace, so the main application of switch-mode power supplies in power amps would be dynamically adjusting the rail voltage of a linear amplifier to reduce the amount of power being dissipated in the output transistors on average.

Since the Axiom amps are basically "switch-mode amplifiers" they can use a simple (but big-ass) power supply without burning energy up as heat anywhere.